Tapping device for molten metals



Jan. 28, 1958 M. TAMA 2,821,378

TAPPING DEVICE FOR MOLTEN METALS 2 sheets-'sneer 1 y Filed Feb. 28, 1955AcruATlN' IN V EN TOR.' MAmo TAMA,

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Jan. 28, 1958 M. TAMA TAFPING DEVICE FoR MOLTEN METALS 2 Sheets-Sheet 2Filed Feb. 28, 1955 INVENTOR- MAmo TAMA,

United l States Patent O TAPPING DEVICE FOR MOLTEN METALS Mario Tama,Morrisville, Pa., assignor to Ajax Engineering Corporation, Trenton, N.J., a corporation of New Jersey Application February 28, 1955, SerialNo. 490,940

Claims. (Cl. 266--42) The invention relates to furnaces for molten metaland relates more particularly to tapping devices for the control of theoutlet of molten metal from such furnaces.

Heretofore, the conventional method of tapping metals from such furnaceswas to provide the furnace with a tapping hole at or near the bottom ofthe furnace and closing the hole temporarily with clay or similarmaterial. This temporary closure was opened with the aid of a rod andthen the metal permitted to ow out in a stream, in` most instances intoa ladle, until either the furnace was emptied or a new closure made byintroducing a ball of re clay into the tapping hole by means of a rod.

lt has been proposed to provide other means for tapping melting pots orfurnaces, but these attempts have not been successful for use withmetals of highmelting point such as aluminum, steel, brass and the like,as the mechanisms of these proposals are subject to dissolution by theprevailing contact with the high temperature molten metal.

The instant invention has among its objects the provision of a tappingdevice that may be used with high temperature molten metals and beopened and closed at will without destruction to the closure, and whichwill promote a continuous and free ow easily controllable so that themetal may directly 'be discharged into a mold.

This application is a continuation-impart of my copending applicationSerial No. 29,263 that was filed on May 26, 1948, now Patent No.2,707,718, dated May 3, 1955.

Fiurther objects and advantages of the invention will be set forth inpart in the following specication and in part will be obvious therefromwithout being specifically referred to, the same being realized andattained as pointed out in the claims hereof.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following;detailed description, taken inconnection with the accompanying drawings, in which: i

Fig. 1 is a plan view of a furnace for molten metal having a tappingdevice in accordance with the invention;

Fig. 2 is a sectional View taken on line 2--2 of Fig. l;

Fig. 3 is a large-scale fragmentary sectional view showing a detail ofthe tapping device; and

Fig. 4 is a fragmentary sectional View, similar to Fig. 3, but embodyinga modication.

In carrying the invention into eiect in the embodiments which have beenselected for illustration in the accompanying drawings and fordescription in this specification, and referring now particularly toFigs. l and 2, there is provided a furnace for molten metal generallyindicated at 11, which may either be a metal furnace or a holdingfurnace.

The furnace 11 is lined with refractory material 12 along the side wall13 and the bottom 14, and Ihas heating means generally indicated at 16which may be of the induction type such as described in my Patent No.2,539,800, issued January 30, 1951.

The furnace 11 may, in accordance with a preferred embodiment, betiltable about a pivot 17 that acts as a 2,821,378 Patented Jan. 28,1958 ICC fulcrnm. This tilting has the advantage for completely emptyingthe furnace 11 when desired by tilting in the direction 18 and also fortilting it back in a direction 19 to free the tapping device fromcontact with molten metal, should that be desired While metal is stillin the furnace.

A tapping device generally indicated at 21 is provided in the side wall13. It comprises a tube 22 that is sealed into an inclined bore 23 thatis formed in the side Wall 13. The tube 22 forms with the horizontal anacute angle and extends through the wall 13 'upwardly and outwardly inrespect to the metal chamber 24 of the furnace 11. The tube 22 is openat its lower end 26 and at its upper end 27, and is constricted near thelower end 26. The lower end 26 Ihas an inlet 28 that has a smallercrosssectional area A than the interior cross-sectional area B of theremainder of the tube 22.

A constriction is provided by an annular apertured valve seat element 29that is formed near the inlet 28; the element 29 has an area C ofaperture that is smaller than the area B, and it has an annular conicalsurface 31, which surrounds the aperture of the element 29 and faces theupper end 27, and that surface 31 defines a valve seat. A valve closureelement such as a stopper 32 fits against said valve seat 31, and iscarried at the end of a rod 33. The rod 33 is movable axially of thetube 22 n in opposite directions 34 and 36 towards and from a valveclosure position wherein the stopper 32 engages the seat 31. The valveseat 31 is immersed in the molten metal not only during pouring but alsoduring the time intervals between .the pours.

The tube 22 is made of heat resistant material, such as refractorymaterial, for instance silicon-carbide, or of similar suitable material.The stopper 32 and the valve seat element 29 are made of heat resistingmaterial, for instance graphite or carbon. The rod 33 may be made ofsteel or cast iron but is covered at least throughout that portion whichreaches into the tube 22 by a layer 37 of heat resistant material, suchas refractory material or a coating of suitable material such as forinstance material known under the trade-name or trade-markSpattershield.

A solenoid, generally indicated at 38, may be carried by a bracket 40attached to the side wall 13, in such a manner that the armature of thesolenoid 38 is connected to the rod 33. Furthermore, a spring 39 may bearranged to bias the rod 33 towards return to its normal positionwherein the stopper 32 engages the valve seat 31. The leads of thesolenoid 38 may be connected to an actuating device 41, s-uch as a pushbutton or a timer (not shown in detail) in order to control the solenoid38 and thereby the rod 33 and stopper 32. Upon energization of thesolenoid 38, it will remove the stopper 32 olf the valve seat 31,against the bias of the spring 39; upon deenergization, the solenoid 38will release the rod 33 to be returned to its normal position under theimpulse of the spring 39 to cause valve closure. i

The upper portion of the tube 22 is surrounded by an electric heatercoil 42 that may be energized to prevent freezing of the metal in thetube 22. When the valve is closed, the metal stands in the tube 22 atthe level 43, close to the lower tip of the upper end 27. The metallevel 44 in the chamber 24 is normally higher than the metal level 43causing, upon opening of the stopper 32, a free flow of the molten metaloutwardly 'through the upper end 27 of the tube 22. A mold 46 may bepositioned below the outpouring stream of molten metal for direct'discharge of the molten metal into the mold 4.6,- as best shown in Fig.2.

A steel jacket 47 is provided around the upper `portion of the tube 22and is spaced therefrom, forming an annular space 48 that may be filledwith insulating material, for instance plastic insulation 49.

In the modification shown in Fig. 4, there is provided a removable unit50 that comprises a cover plate 141 which is surrounded by a steeljacket 147; the steel jacket 147 is applied against the side wall 113 ofthe furnace 1111 and may removably be secured thereto, for instance by'screws 52 applied to a iiange 53 of the steel jacket 147. The cover 51has an inclined bore 123 into which is sealed the tube 122. The chamber124 of the furnace 111 hasl a channel 54 into which the tube 122reaches, dipping into the molten metal that lls the channel 54, and thecover plate 51 is applied to close the channel 54.

A space 148 is provided between the steel jacket 147 and the tube 122,and insulating material 149 and a heater coil 142 are located in thatspace 148. The bracket 140 may be attached to the cover 51; the otherparts, the rod 133, the stopper 132, and the valve seat 131, operate inthe same way as in the previously described embodiment.

The operation of the above described invention is as follows.

Energization of the solenoid by the actuator 41 will remove the stopper32 of the valve seat 31, and molten metal will flow from the chamber 24through the tube 22, and will be discharged in a free flow off the lowertip of the open end 27 of the tube 22. The molten metal owing into thetube 22 through the aperture of the valve element 29, which forms aconstriction relative to the interior cross sectional area B of the tube22, will ow easily and continuously from the chamber 24 into the tube22. The constriction which is immersed in the metal bath promotescontinuous flowing by preventing build-up, and this is apparently causedby the rapid flow through the constriction. The metal emerging from thetube 22 in a free ow may be directed to be discharged directly into amold 46. Upon deenergization of the solenoid 38, the spring 29 willreturn the stopper 32 to close the valve; similarly, upon power failure,the solenoid will be de-activated and the spring 39 will act to closethe valve in the same manner.

As best shown in Figs. 3 and 4, the tube 22 (122) is during theintervals between pours iilled with molten metal to the level 43 nearthe pouring lip, so that upon lifting of the stopper 33 (133) the tubewill substantially without delay start pouring the metal in a freegentle parabolic flow, for instance into the mold 46.

The furnace 11 may be tilted about the fulcrum 17, either in direction18 when the metal level 44 has become too low for normal gravitationaldischarge through the tube 22 in the normal position of the furnace 11,or be tilted in direction 19 to free the lower end 28 of the tube 22from contact with molten metal.

It will be apparent to those skilled in the art that the novelprinciples of the invention disclosed herein in connection with specificexemplications thereof will suggest various other modifications andapplications of the same. It is accordingly desired that in construingthe breadth of the appended claims they shall not be limited to thespecific exemplilcations of the invention described herein.

Having thus described the invention, what I claim as new and desire tobe secured by Letters Patent, is as follows:

1. In a tapping device, for use in connection with a furnace for moltenmetal having a bottom and a side wall defining a chamber for the moltenmetal bath, in combination, a tube having a solid uninterruptedencircling wall and being open at both ends protruding through said sidewall and being inclined at an angle to the horizontal plane and adaptedto extend with its lower end into the metal bath in said chamber andwith its upper end to the exterior of said furnace, said tube beingcomposed of heat resistant material and having near itslower end aconstriction, a valve seat formed near said constriction on the tubeinterior and adapted to be immersed in the molten metal during pouringand during the time intervals Ibetween pours, and a stopper on theinterior of said tube movable Within said tube in opposite directions toand from said valve seat for releasably sealing the same and including astem extending from said stopper through said open upper end to theexterior of said tube, the molten metal filling said tube between poursto a level slightly below the pouring level and below the level in thefurnace, whereby upon removal of said stopper off said seat molten metalmay ow upwardly through said tube and thereafter in a free constant flowemerge from the upper end of said tube.

2. In a tapping device, as claimed in claim 1, together with, heatingmeans surrounding at least the upper portion of said tube forrestraining metal freezing therein.

3. In a tapping device, as claimed in claim 1, together with, a metalcasing surrounding at least the upper portion of said tube and spacedtherefrom dening with the exterior of said tube portion an annularspace, and insulating material disposed in said space.

4. In a tapping device, as claimed in claim 1, together with, meansoperatively connected to said stem and operable for guding said stopperto and from its sealing position on the valve seat, resilient meansactuatable to urge said stopper towards said seat for normally closingthe valve, and a mechanism energizable to move said stopper away fromsaid valve seat against the bias of said resilient means and arranged torelease said stopper upon deenergization for return thereof under theimpulse of said resilient means.

5. In a tapping device unit, for use in connection with a furnace formolten metal including a bottom and a side wall dening a chamber for themolten metal bath including a lateral channel formed in said side wallbelow the normal metal level, in combination, a side cover secured tosaid side wall adjacent said channel and having a larger dimension thanthe cross-section of said channel to close the same throughout, saidcover comprising a wall having a bore inclined upwardly when said wallis positioned on said furnace intercommunicating with the interior ofsaid channel, a refractory tube disposed in said channel and open atboth ends and extending with its upper end to the exterior of said walland extending with its lower end into said channel, said lower end beingin said channel immersed in the molten metal bath, and having aconstriction and adapted to be immersed in the molten metal bath, avalve seat formed near said constriction, and a stopper movable on theinterior of said tube in opposite directions to and from said seat forreleasably sealing the same and including a stem extending from saidstopper through said open upper end of said tube to the exterior, themolten metal filling said tube between pours to a level slightly belowthe pouring level, whereby upon removal of said stopper oif said seatmolten metal may ow upwardly through said tube and thereafter in a freeconstant ilow emerge from the upper end of said tube.

References Cited in the le of this patent UNITED STATES PATENTS1,027,821 Cunningham May 28, 1912 1,162,246 Menough Nov. 30, 19152,112,161 Kelly Mar. 22, 1938 2,426,644 Van der Pyle Sept. 2, 19472,535,335 Thevenin Dec. 26, 1950 2,587,727 Horswell et al. Mar. 4, 19522,676,011 Loftus et al Apr. 20, 1954 2,678,480 Lapin May 18, 19542,713,705 Lapin July 26, 1955 2,745,153 Burkett May 15, 1956 FOREIGNPATENTS 702,833 Great Britain Jan. 27, 1954

